Amino acids in collision residue support importance of extraterrestrial impacts
Smacking a steel projectile into a comet-like icy concoction has produced the ingredients for making proteins. The findings add weight to the hypothesis that primordial life on Earth arose from the wreckage of comet collisions.
Space debris relentlessly pummeled Earth when life began, an estimated 3.8 billion years ago. Some scientists think that icy carbon-bearing comets delivered life’s ingredients. Energy from the impacts may have catalyzed the transformation of simple carbon compounds into amino acids, the building blocks of proteins – a key type of molecule for life.
To recreate the ancient conditions, scientists led by Zita Martins of Imperial College London made an icy mixture of compounds that exist on comets; they used ammonium hydroxide, carbon dioxide and methanol. Then researchers hurled a steel projectile into the icy mix at 7.15 kilometers per second.
The scientists report September 15 in Nature Geoscience that residue from the impact contained amino acids including glycine, alanine and isovaline.
Z. Martins et al. Shock synthesis of amino acids from impacting cometary and icy planet surface analogues. Nature Geoscience. Posted online September 15, 2013. doi:10.1038/ngeo1930. [Go to]